Field of the Disclosure
The present disclosure relates to, inter alia, computerized apparatus and methods for detecting features in sensory information.
Description of Related Art
Saliency is a term often used in psychophysics and neuroscience, where it may be defined as the ability to attract attention to a particular stimulus. In the visual modality, saliency may be attributed to objects or visual patterns. In primates, there are at least five general aspects of the visual scene which spontaneously attract attention (a phenomenon often called pop-out):                1. Color—a unique color surrounded by another color or colors (e.g., a red spot in sea of green) will involuntarily trigger attention.        2. Orientation—a bar of one orientation surrounded by bars of another orientation        3. Contrast (luminance)—an area characterized by large contrast (a bright thing mixed with very dark things)        4. Motion—an object moving in a different direction or speed that surroundings.        5. Faces—only for humans and some primates, image resembling a face        
The biological origin of this behavior is debated. One of the plausible mechanisms is local inhibitory interaction in visual cortex (and perhaps thalamus). Such inhibitory connections arise between neurons which represent things often co-occurring. For example, a segment of vertical line (observed by a spatially restricted receptive field of a neuron) is typically a fragment of a larger line. A color blob seen in a receptive field of a neuron is most often a fragment of a larger blob of the same color. Appearance of a feature (e.g., orientation) which is not expected in a given context (e.g., vertical line segment surrounded by a large number of horizontal lines) is statistically much more rare, therefore inhibitory connections for such occurrence are much weaker. In consequence, the response of a neuron representing such “unexpected features” is stronger, as the otherwise present inhibition is lacking.
From an evolutionary point of view, sensitivity to such unexpected stimuli is beneficial. It allows one to quickly detect anomalies in the visual scene, which often indicate behaviorally relevant information (e.g., a ripe, red fruit among green leaves, a dangerous predator hiding in the bushes).